Revert "Revert "[generator] Remove androidx.annotation from Annotation names (#882)""

This reverts commit 3f12cd2.

Author: jpobst

src/Xamarin.Android.Tools.AnnotationSupport/Objects/AnnotationData.cs

@@ -7,13 +7,20 @@ namespace Xamarin.AndroidTools.AnnotationSupport
 {
 	public class AnnotationData : AnnotationObject
 	{
+		static readonly string[] Prefixes = new[] {
+			"android.support.annotation.",
+			"androidx.annotation.",
+		};
 		public AnnotationData (XElement e)
 		{
 			var a = e.Attribute ("name");
 			Name = a == null ? null : a.Value;
-			string predef = "android.support.annotation.";
-			if (Name.StartsWith (predef, StringComparison.Ordinal))
+			foreach (var predef in Prefixes) {
+				if (!Name.StartsWith (predef, StringComparison.Ordinal))
+					continue;
 				Name = Name.Substring (predef.Length);
+				break;
+			}
 			Values = e.Elements ("val").Select (c => new AnnotationValue (c)).ToArray ();
 		}